Blow box



w. v. HYENRY 2,886,848

BLOW BOX May 19, 1959 Filed Feb. 10, 1955 2 Sheets-Sheet l MCI/UM INVENTOR mm'm warml ATTORNEY 2 Sheets-Sheet 2 INVENTOR BY W a? ATTORNEY May 19, 1959 w. v. HENRY BLOW BOX Filed Feb. 10, 1955 Unite States atent 2,886,848 BLOW BOX William V. Henry, Candler, N.C., assiguor to American Enka Corporation, Enka, N.C., a corporation of Dela- Ware Application February 10, 1955, Serial No. 487,341 Claims. (Cl. 18-8) This invention relates to the melt spinning of polymeric materials and more particularly to the protection of spinning personnel and equipment from monomers present in the melt and vaporized incident to the spinning operation.

In the melt spinning of polymeric materials, such as caprolactam polymers and the like, it is customary to polymerize the monomer and then to heat the resulting polymer enough to liquify it so that it can be extruded through a spinneret. After extrusion the polymeric material in thread form is cooled to solidification and collected in suitable form for use..

Of course, the polymerization of a monomer is never one hundred percent complete with the result that monomers are present in the polymerized product as contaminants. These are rendered gaseous by the heat which liquifies the polymer and, upon coolnig, these gases tend to condense on and around the spinneret and cooling chamber causing undesirable incrustations which interfere with the spinning. Furthermore, uncondensed vapor of caprolactam monomers is unpleasant to personnel in the spinning rooms.

It is an object of this invention to protect both personnel and equipment from volatile contaminants of the melt which are evolved during spinning.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description of an embodiment thereof in conjunction with the annexed drawings wherein:

Figure 1 is a view partially in elevation and partially in vertical section showing a spinning position for melt spinning incorporatng the present invention;

Figure 2 is a top plan view to an enlarged scale of the vapor recovery apparatus of the present invention;

Figure 3 is a view in vertical section taken on the line 3--3 of Figure 2;

Figure 4 is a view in vertical section taken on the line 4-4 of Figure 2;

Figure 5 is a view in vertical section taken on the line 5-5 of Figure 2; and

Figure 6 is a view in detail of one of the water nozzles with which the equipment of the present invention is provided.

In Figure 1 the numeral 10 designates a spinning head which incorporates a spinneret 11. Yarn 12 issuing from the spinneret 11 is cooled in a vertically disposed blow box 13 which leads to a chimney 14 as is conventional in the melt spinning of polymeric materials. In this assembly, applicants annular chamber 15 is located between the spinning head 10 and the blow box 13 coaxially with respect to the axis of the spinneret 11 and the path of the freshly formed yarn 12. The function of the present invention is to draw the gases emanating from the hardening yarn 12 and mixed with the cooling air flowing upwardly in the blow box away from the spinneret 11 and to dissolve any soluble constituents thereof. The cooling air for the illustrated system enters the blow box 13 at the bottom through the generally annular space 16 between the blow box 13 and the chimney 14. It is not necessary that the air enter at this location. The cooling air may optionally enter through an opening (not shown) in the Wall of blow box 13. In this case, there would be a comparatively tight fit between blow box 13 and chimney 14.

The annular chamber 15 is provided with a generally vertical outer wall at .17 and an inner wall at 18 which slopes inwardly from bottom to top to define a frusto conical central space through which the freshly extruded yarn passes on its way to the blow box. The wall 18 has two large access slots or ports 19 and 20 therein which lead to the interior of the chamber 15. Ducts 21 and 22 lead generally tangentially away from the chamber 15 and constitute the outlets therefor. The outer wall 17 of the chamber 15 is interrupted so that the interior of the chamber can communicate with the interior of the ducts 21 and 22, see Figures 3 and 4.

In each duct 21 and 22 there is located a water nozzle 23. Each nozzle 23 has a downstream aperture at 24 directed toward the discharge or outlet end of the respective duct 21 or 22. Water is supplied to these nozzles through conduits 24 and 25, see Figure 1.

Structurally the nozzles 23 are supported by the bot tom wall 26 of the chamber 15 which extends beyond the chamber annulus to function as the bottom wall for the ducts 21 and 22. The top wall of the chamber 15 is laminated and is comprised of an inner metal annulus 27 and an outer annulus 28 of heat insulating material. The annulus 28 protects the chamber 15 from the heat of the spinning head. The upper walls of the ducts 21 and 22 are not coplanar with the wall 27, see Figure 4.

Because the ducts 21 and 22 are supplied. with water through their respective nozzles 23, they are provided with downwardly sloping ends at 21a and 22a. Thus the water drains off by gravity. The ducts: 21 and 22 are connected to an evacuating pump, not shown, so as to create a substantial negative pressure in the chamber 15.

It can now be seen that gases evolved incident to spinning are drawn into the chamber 15 through slots 19 and 20. This direction of flow is brought about by the negative pressure maintained within the chamber 15 by the suction applied to the ducts 21 and 22. As these gases pass out of the annular chamber 15 into the ducts 21 and 22 they pass through a water spray which dissolves their soluble constituents. These constituents are recovered in and hence with the water, and the remaining washed and innocuous gases are discharged to atmosphere. Because any monomers in gaseous form which are present at the spinneret are quickly drawn away and dissolved, the incrustation problem around the spinneret and blow box is avoided.

What is claimed is:

1. Apparatus for removing gaseous contaminants from the ambient atmosphere of a spinning position for the melt spinning of polymeric material that comprises a spinning head including a spinneret, a blow box spaced below said spinning head and arranged to receive the freshly spun yarns issuing from the spinneret, chamber means bridging the space between said head and box and surrounding the yarn path therebetween, said chamber means having an inner port and an outlet, means establishing a spray of liquid within said chamber means between said port and said outlet, and means to apply suction to said outlet to draw gaseous contaminants from the vicinity of the spinneret and to pass them through said spray of liquid.

2. Apparatus for removing gaseous contaminants from the ambient atmosphere of a spinning position for the melt spinning of polymeric material that comprises a spinning head including a spinneret, a blow box spaced below said spinning head and arranged to receive the freshly spun yarns issuing from the spinneret, chamber means bridging the space between said head and box and surrounding the yarn path therebetween, said chamber means having ports in its inner walls parallel to said yarn path, said chamber means also having outlets, spray nozzles located between said inner wall ports and said outlets and means to apply suction to said outlets whereby to draw gaseous contaminants from the vicinity of the spinneret and to pass them through the sprays of liquid issuing from said nozzles.

3. Apparatus for removing gaseous contaminants from the ambient atmosphere of a spinning position for the melt spinning of polymeric material that comprises a spinning head including a spinneret, a blow box spaced therebelow, an annular chamber bridging the space between said head and box and surrounding the yarn path therebetween, said chamber having inner and outer ports, suction producing means, a duct connecting each outer port to said means and a nozzle in each duct for forming a spray of water through which gas flowing in the duct must pass.

4. Apparatus for removing gaseous contaminants from the ambient atmosphere of a spinning position for the melt spinning of polymeric material that comprises a spinning head including a spinneret, a blow box spaced therebelow, an annular chamber bridging the space between said head and box and surrounding the yarn path therebetween, said chamber having inner and outer ports, suction producing means, a downwardly sloping duct connecting each outer port to said means and a nozzle in each duct for directing a spray of liquid in a down- I stream direction.

5. Apparatus for removing gaseous contaminants from the ambient atmosphere of a spinning position for the melt spinning of polymeric material that comprises a spinning head including a spinneret, a blow box spaced below said spinning head and arranged to receive the freshly spun yarns issuing from the spinneret, chamber means bridging the space between said head and box adjacent the yarn path, said chamber means having at least one inner port and at least one outlet, means establishing a spray of liquid within said chamber means between said inner port and said outlet, and means to apply suction to said outlet to draw gaseous contaminants from the vicinity of the spinneret and to pass them through said spray of liquid.

References Cited in the file of this patent UNITED STATES PATENTS 

